645018677 has 2 divisors, whose sum is σ = 645018678. Its totient is φ = 645018676.

The previous prime is 645018617. The next prime is 645018713. The reversal of 645018677 is 776810546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 642825316 + 2193361 = 25354^2 + 1481^2 .

It is a cyclic number.

It is not a de Polignac number, because 645018677 - 2²⁴ = 628241461 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645018617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322509338 + 322509339.

It is an arithmetic number, because the mean of its divisors is an integer number (322509339).

Almost surely, 2^645018677 is an apocalyptic number.

It is an amenable number.

645018677 is a deficient number, since it is larger than the sum of its proper divisors (1).

645018677 is an equidigital number, since it uses as much as digits as its factorization.

645018677 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 282240, while the sum is 44.

The square root of 645018677 is about 25397.2178988172. The cubic root of 645018677 is about 864.0205993067.

The spelling of 645018677 in words is "six hundred forty-five million, eighteen thousand, six hundred seventy-seven".